Cathode-ray polar coordinate vector plotter



Nov. 27, 1951 A. H, WAYNICK CATHODE-RAY POLAR COORDINATE VECTOR PLOTTER.I LLL- i.

Filed April l0, 1948 SCOPE scRff/V ECTRO/V/C SWITCHES IN VEN TOR.

Patented Nov. 27, 1951 UNITED STATES PATENTv OFFICE by mesne4assignments, to The Pennsylvania Research C0 rpofratiortl a corporationof Penn- Sylvania Aliplicatox'l-April 10, 1948, Serial No. 20,215

1 My invention relates broadly to measuringnin struments and moreparticularly toa' vectm presenter for visually displaying-` conditionsin electrical circuits in polarV coordinatesf O ne of the objects of myinventionisto mcvidev a. circuit arrangement l'or acathode ray tubesysteml for visually. displaying Acor.ldlltenit mmultiplicity of relatedelectrical. circuits accord.- l ing. to polar coordinates. c

Another object of my invention is to provide an arrangement of vectorpresentar for simultaneously displaying a multiplicity. of vector@auditions in an e1= ,=t1'.a1A Circuit" Where.. the t Vectorshave aCommon origin. at *t1-.latenter ef the: oscilloscope screen.` Y lAnother object of my invention is to provide a circuit system fordirectly measuring vector conditions in a multiplicity of electricalcircuits and displaying the vector conditions on a cathode rays/creen inaccordance'with phase andrvoltafge conditions existing in the circuits.'I

@ther and further objects'- of my invention reside in the provision of aprecision circut'fori acathede my 1191er codrdina'te vector plottei'insimpliiied'form asset forth in thespecication hereinafterfollowing byreference to the acc-ornpanying drawing, in which: d

Figure l is a iront elevational view; of a; cathode ray screenillustratingl the display of vectors thereon according to conditions ina multiplicity: o'f electrical circuits; and, Fig. 2 is a diagrammaticand schematic circuit arrangement of the` cathode ray polar coordinatevector plotter o fVy my invention.

The# vector presentorof-v myinventionis; aY device for presentingsimultaneously' as manyvv as threev lines havingk a common originvatthe" center of an oscilloscope screen. The lengths of"r the lines areproportional toV the magnitudes of as many as three voltagessimultaneously' impressed on the'device. The included angles-be"- tweenthe lines are equal to the: phasel angles. between the voltages.

Referring to Fig. 1, I have shown a cathode-1 ray oscilloscope screenhavingdisplayed thereon electrical conditions in threel electricalcircuitsI by vectors A, B and C phased with respect-to each'- other byangle A. B and angle A, Q forl denoting 'lhedrop' across the loadresistor' 2' is appliedV the. X deflection plates 4-5 o'fan oscilloscopethrough isolating resistors I9V iny suchV a manner that thev resultingpattern is a straight line with;

origin atthefcenter 'of the screen representedv at 1rv in' ne; .1;Thiosalnscgaei mandame.

. 2 hina-tion with an electronic beam generatory the X deiiecting platesll and 5 and the Y deflecting' plates 8 and 9 electrically controllingthe sweep of the electronic beam propagated between the electrodes 4,5.13am@ t in the eld 3l for titanbardment 0f the' sensitized Screen 1-The lensth of the line isrropotional t0 the ampltuseof.. theigiak, The1111 extends alone a horizontal; existo the right which is consideredzero phase on a polar coordinate system superimposed on a Cartesiancoordinate system set up by the sets of deilecting plates shown at 4 5and 8 9. The reference signal is also amplied and clipped throughapparatus l0 and passed through diferentiator ll. This results inpositive and negative pip-s at the zero and k180 phase points of thereference signal respectively. vThe'A positive pips actuate a. singlesided', positivev o perated, triggered multi-vibrator l; which remainsactuated.l forl a suitable" length or tii'ne independent; of the inputsignaiarnplitude'l and frequency. This time is chosen; to be short; in'

terms-v cf the signaly period; about l/aeo; When the" multi-vibrator `I2- is triggered it actuates t'wfov electronic switchesv Hand l'showninthe outputjofV the signal Bcircuit; t c

Signal B isapplied atterminal" bV through' a 0" or' i809 phase shiftershownat I6 tothe inputlof one'g'cf the switching tubes I4 directly andthrough a99" network I8 tothe input of the other switchiiiig tube 155Electronieswitcnm connects tothe-r ad, tor* short time thereater.- andare @een for the remainder. of. the time. A; description-.oir the4operation is most'easily` explained mathematinur;

efr:A sin wi be'-"th'reference f signal whe'r'e" the instantaneous.ivalue of the reference t are Open! -Bt Signaliserelied and@ asset;atti-1e Crista. flma'erpearsce the Seppe face l,

When e A goes through the B switches I4 and I5 are closed and a voltageeM=EB sin (wt-MB) is applied to the Y plates 8 and 9. Simultaneous'-I lya voltage =Ea cos (wt-l-qba) is applied to the X plates 4 and 5.

appears in this expression due to the 90 line. The net deflectionvoltage actuating the spot is then 1 and consequent deection obtained isj tan-1sin im e,B EB e cos :E B61' E This is a Vector, or line on thescope face `I, having an amplitude EB and at an angle with respect tothereference trace of B as desired.

Signal C applied at terminal c may be treated in the same manner assignal B with the following dierences. The reference signal C circuit includes the 180 or 0 phase shifter I1 connected to one of the electronicswitches 24 directly abd through a 90 p hase shifter 23 to the otherelectronic switch 25. Electronic switch 24 connects to the Y plates 8and 9 through isolating resistor 26 while electronic switch 25 connectsto X plates 1I and 5 through isolating resistor 2'I. The circuits arecoordinated in their mutual operation by the connection of asingle-sided negative-operated triggered multi-vibrator 28 connectedfrom differentiator II through limiting resistor l29 `and the half waverectifier 30 with the electronic switches 24 and 25 as shown. It isnecessary that the line representing signal C voltage be swept acrossthe tube face I at some time when 'the lines B and A are not being sweptout. This is accomplished by closing the C switches when the referencesignal goes through 180; i. e., when wt=(2n-1)1r. Suitable phasing isobtained vby adding a 180 phase shift in the C circuit as shown.

It is evident that the three lines constituting the display are sweptout at different times and,

for the B and C signals, during the time of closure a of the switches.Visual integration is obtained by the oscilloscope phosphor andvpersistence of vision so that the three lines appear simultaneously tothe observer.

In operation, the two multi-vibrators I2 and 28 are triggeredrespectively by the vpositive andr negative pips resulting fromdifferentiation of the output of the amplifier and clipper I0whose'output, in turn, is due to the reference signal A. This triggeringcauses the multi-vibrators I2 and, 28 to put out a rectangular pulsehaving a length of approximately 1/560 or onev angular degreeof wavelength of reference signal A. Since Athe two multi-vibrators I2 and 28are positively and negatively operated, the positively initiatedl pulseloccurs at 0 phase with respect to reference A, while the negativelytriggered pulse occurs at 180 i phase with respect to reference A. Eachpositive equivalent to the length of the pulse, to pass the component ofsignal B or signal C with whatever amplitude they may have at that time.Thus, the two components of signals B and C are applied to theoscilloscope defiection electrodes 4 5 and 8-9 in such a way as to givevector lines on the y oscilloscope face angles of orientation of whichzero phase and for a short period thereafter and and means for applyingsignal energy from saidvv with the positive horizontal are the phaseangles between those signals and reference signal A and the amplitudesof which are proportional to the amplitudes of signal B and C,respectively. On a time basis, signal B will appear first on theoscilloscope face; reference signal A, after passing through thehalf-wave rectier 30 then ap pears on the oscilloscope face as apositive horlzontal line of amplitude proportional to theamplitude ofsignal A and providing a zero phase reference for the othei` twovectors; signal C then appears followed by a half-period of no signal tothe oscilloscope.

For the 'case illustrated, the oscilloscope pattern Vwill-be thatillustrated in Fig. 1, with phase angles approximately as follows: y

I have found the cathode ray polar coordinate vector plotter of myinvention very eiiicient for quickly analyzing conditions in a pluralityof coacting electrical circuit systems. I realize, however, thatmodification in detail of the circuit:

. may be made and I desire that it be understood screen, a plurality ofinput circuits excitable from4 signal energy, one of said input circuitsbeing excitable from a reference signal voltage, a pair ofmulti-vibrator circuits having inputs and outputs, connections betweensaid last mentioned input circuit with the inputs of said pair ofmultivibrator circuits, two pair of electronic switches.

the output of one of said multi-vibrator circuitsf being connected withone pair of said electronic switches and the output of the other of saidmulti` vibrator circuits being connected with the other Vpair of saidelectronic switches, connections from said electronic switches to saidsets of control electrodes, said electronic switches being closed' whenthe reference signal voltage passes through opened for the remainderofthe time for Ydetermining the phase points of the reference voltage,

other input circuits to said sets of control electrodes at the referencephase instances for vectorially controlling the sweep of the electron.'beam with respect to said screen for visually re' producing the phaseangles ofthe currents apr' plied`-'to"said input'circuits, vtogetherwith lan inl termediate reference line established by currents appliedto said first mentioned input circuit.

2. A vector presentor as set forth in claim i, in which a vrectifier isinterposed between-said first mentioned input circuit and the circuit.connections to said sets of control electrodes.

3. A vector presentor as setforth in claim l, in which one of saidmulti-vibrators operates at positive polarity and the other of saidmultivibrators operates at negative polarity for selectively controllingthe respective pairs of electronic switches connected therewith.

4. A vector presentor as set forth in claim 1, in which phase shiftmeans are interposed between said last mentioned input circuits and saidpair of electronic switches for controlling the sweep of the electronbeam incident to the signal currents applied to said last mentionedinput circuits and rendering the electron beam successively effectiveunder control of the respective input circuits for reproducing visualtraces on said oscilloscope screen in recurring displaced time sequence.

5. A vector presentor comprising in combination, an oscilloscopeincluding a screen for reproducing vectors under bombardment by anelectron beam, sets of control electrodes for c'ontrolling the vectorialsweep of the beam over said screen, a plurality of input circuitsexcitable from signal energy, one of said input circuits being excitablefrom a reference signal voltage, a pair of multi-vibrator circuitshaving inputs and outputs, connections between said last mentioned inputcircuit with the inputs of said pair of multi-vibrator circuits, twopair of electronic switches, the output of one of said multi-vibratorcircuits being connected with one pair of said electronic switches andthe output of the other of said multi-vibrator circuits being connectedwith the other pair of said electronic switches, connections from saidelectronic switches to said sets of control electrodes, said electronicswitches being closed when the reference signal voltage passes throughzero phase and for a short period thereafter and opened for theremainder of the time for determining the phase points of the referencevoltage, phase shift means interposed between said other input circuitsand one of each of the electronic switches of said pair of electronicswitches and additional phase shift means connected between said lastmentioned phase shift means and the other electronic 4switches of eachof said pair of electronic switches respectively for controlling thesweep of the electron beam incident to the signal currents applied tosaid last mentioned input circuits successively under control of therespective input circuits and in recurring displaced time sequence forVectorially controlling the sweep of the electron beam Vwith respect tosaid 'screen for visually reproducing the phase angles of the currentsapplied to said last mentioned input circuits together with anintermediate reference line established by currents applied to said rstmentioned input circuit.

6. A vector presentor comprising in combination, an oscilloscopeincluding a, screen for reproducing vectors under bombardment by anelectron beam, sets of control electrodes for controlling the vectorialsweep of the beam over said screen, a plurality of input circuitsexcitable from signal energy, one of said input circuits being excitablefrom a reference signal voltage, a pair of multi-vibrator circuitshaving inputs and outputs, connections between said last mentioedinputcircuity with the inputs of said pair of multi-vibrator circuits, twopair of electronic;

switches, the output of one of said multi-vibrator circuits beingconnected with one pair of said electronic switches and the output ofthe other of said multi-vibrator circuits being connected with the otherpair of said electronic switches, connections from said electronicswitches to said sets of control electrodes, said electronic switchesbeing closed when the reference signal voltage passes through zero phaseand for a short period thereafter and opened for the remainder of thetime for -determining the phase points of the reference voltage, a 0 or180 phase shift circuit interposed between one of said last mentionedinput circuits and one set of said electronic switches and a 180 or 0phase shift circuit interposed between another of said last mentionedinput circuits and said other set of electronic switches, respectively,for controlling the sweep of the electron beam incident to the signalcurrents applied to said last mentioned input circuits successivelyunder control of the respective input circuits and in recurringdisplaced time sequence for vectorially controlling the sweep of theelectron beam with respect to said screen for visually reproducing thephase angles of the currents applied to said last mentioned inputcircuits together with an intermediate reference line established bycurrents applied to said first mentioned input circuit.

7. A vector presentor comprising in combination, an oscilloscopeincluding a screen for reproducing vectors under bombardment by anelectron beam, sets of control electrodes for controlling the vectorialsweep of the beam over said screen, a plurality of input circuitsexcitable from signal energy, one of said input circuits being excitablefrom a reference signal voltage, a pair of multi-vibrator circuitshaving inputs and outputs, connections between said last mentioned inputcircuit with the inputs of said pair of multi-vibrator circuits, twopair of electronic switches, the output of one of said multi-vibratorcircuits being connected with one pair of said electronic switches andthe output of the other of said multi-vibrator circuits being connectedwith the other pair of said electronic switches, connections from saidelectronic switches to said sets of control electrodes, said electronicswitches being closed when the reference signal voltage passes throughzero phase and for a short period thereafter and opened for theremainder of the time for determining the phase points of the referencevoltage, a. 0 or 180 phase shift circuit interposed between one of saidlast mentioned input circuits and one of the electronic switches of onepair of said electronic switches, an additional phase shift circuitconnected between the aforesaid phase shift circuit and the otherelectronic switch of said last mentioned pair of electronic switches anda or 0 phase shift circuit interposed between another of said lastmentioned input circuits and one of the electronic switches of saidother pair of said electronic switches, an additional 90 phase shiftmeans connected between the last mentioned phase shift circuit and theother electronic switch of said last mentioned pair of said electronicswitches, respectively, for controlling the sweep of the electron beamincident to the signal currents applied to said last mentioned inputcircuits successively under control of the respective input circuits andin recurring displaced time sequence for vectorially controlling thesweep of the electron beam with respect-to said screen for visuallyreproducing the phase angles UNITED STATES PATENTS of the currentsapplied to said last mentioned 1n- Number Name Date Y Dutcircuitstogether with an intermediate refer- 2'012'480 Reich Aug. 27' 1935 enceline established by currents appliedrto sai 5 V2,089,430 Roys et a1 Aug10I 1937 rst mentioned input circuit. 2,221,115 Shepard Nov 12' 1940ARTHUR H WAYNICK- 2,318,197 ci-ark May 4, 1943 7 1 REFERENCES CITED`23.66 35 Schlesinger Jan 2 The following references are of record inthe m le of this patent: y

